I think that imagining a cyclist as being 7 foot wide plus 3 foot o/t distance is a bit ott.
Be realistic. I'm happy with 3 foot clearance.
But I agree that a lot of drivers think its ok to be as close as they can as long as they dont knock you off.
Before I started cycling again (2 years ago),after 30 years as a car driver I am ASHAMED to say that on some occasions I have been that close to a cyclist that I had to look in my rear view mirror to see if I had knocked him/her off or not. Im not alone too!
Cycling again has really opened my eyes to the dangers posed by such close passes.
Plus there's the fear factor that I never appreciated. I've not sh**e myself yet but i've come pretty close at times. believe me !
If a car driver hasnt been on a bike in todays traffic then he/she wont appreciate the dangers.
Education for me has gotto be the key to make the roads safer for cyclists.
Remember the think once, think twice, think bike campaign of the 70-80s for motorbike. Maybe a gvt sponsored campain to educate drivers to the cyclist?
I think that the op's little chat with the driver of the RR will improve his appreciation of cyclists no end, even if he didnt show it at the time.